CN103045188B - Plugging-type filtrate reducer for water-based drilling fluid and preparation method thereof - Google Patents

Abstract

The invention relates to a plugging fluid loss reducer for drilling fluid and a preparation method thereof. The fluid loss reducer can be selected according to the temperature of the applicable well section and the characteristics of the formation. Its composition includes polymer modified oxidized asphalt (PMA), modifier and auxiliary fluid loss reducer. Through simple surface modification and dry The fluid loss control agent series samples can be prepared by mixing process. The sample of the present invention has excellent performance in reducing drilling fluid fluid loss, the reduction rate is as high as 80%, and forms a dense and tough mud cake. The high-temperature softening and deformation characteristics of asphalt can seal formation cracks and fissures in time, and can be selected according to the characteristics of the application formation and the temperature of the well section Suitable product formula, flexible use, simple production process, mild conditions, high production efficiency, low cost, no waste gas and dust, and little physical injury to operators.

Description

Plugging fluid loss reducer for water-based drilling fluid and preparation method thereof

technical field

The invention belongs to oilfield chemicals used in water-based drilling fluid systems, in particular to a plugging fluid loss reducer used in water-based drilling fluids and a preparation method thereof.

Background technique

The functions of water-based drilling fluid mainly include the following aspects: carrying cuttings, cooling drilling tools, plugging and preventing collapse, reducing water loss, lubricating drill bits, transmitting information, assisting rock breaking, balancing and controlling formation pressure, etc. The filtration loss into the formation is one of the main aspects. Fluid loss reducer, also known as fluid loss reducer and fluid loss control agent, can form a low-permeability, flexible, thin and dense filter cake on the well wall, and is a type of oilfield chemical that minimizes the fluid loss of drilling fluid . Fluid loss additives are mainly divided into the following categories: cellulose, humic acid, acrylic polymer, resin and starch.

Among them, fiber products include sodium carboxymethyl cellulose, polyanionic cellulose and sodium carboxyethyl cellulose. For example, US Patent No. US20100828061, such products have excellent fluid loss reduction performance and are applicable to a wide range of systems, but they significantly increase the viscosity of drilling fluid. , expensive, poor temperature resistance.

Humic acid products include lignite lye, sodium nitrohumate, chromium humic acid, sulfomethyl lignite, etc., such as Chinese patents CN1807543 and CN9411858.5. These products can reduce fluid loss and viscosity at the same time, and have a certain resistance temperature, but its filtrate pollutes the environment, destroys oil and gas reservoirs, and the production process conditions are harsh, causing great physical damage to operators.

Acrylic polymers include hydrolyzed polyacrylonitrile ammonium salts, polyacrylate polymers, etc., acrylate multi-polymers, etc., such as Chinese patent CN99100025.0, Chinese patent CN101250397, Australian patent AU2010207511 and world patent WO2011158003. These products also have It has the functions of salt resistance and thickening and cutting, thereby inhibiting shale expansion, and the process is simple, but its calcium resistance is weak, and the temperature resistance is poor, and the raw materials and products have sour taste.

Resin products include sulfomethyl phenolic resin, sulfonated lignite resin, sulfonated lignin sulfomethyl phenolic resin condensate, etc., such as Chinese patents CN99107926.4, CN99107925.6 and CN200710114554.4. These products have good high temperature resistance , has both lubricity and anti-slump properties, but its fluid loss control performance is relatively poor, and it pollutes the environment.

Starch products include carboxymethyl starch, carboxypropyl starch, pregelatinized starch, high temperature resistant starch and modified starch, etc., such as Chinese patent CN201010125334.3. These products belong to natural polymers and their derivatives, and are easy to degrade. Environmental protection is good, but its high temperature resistance is poor, the modification process is complicated, and it is easy to ferment and deteriorate, so it cannot be used and stored for a long time.

In addition, some researchers have used the plugging properties of fibrous or massive materials to prepare fluid loss control agents, such as Chinese patents CN200810236644.5 and CN200710014322. These products are innovative, but their fluid loss control performance is not as good as that of polymers and resins Class, and the high temperature resistance is also limited.

Contents of the invention

In view of the deficiencies of existing research and the urgent needs of practical applications, especially the problems of viscosity increase, cumbersome production process, environmental pollution and high cost in the existing fluid loss control agents for water-based drilling fluids, the present invention aims to solve The problem is to provide a plugging fluid loss reducer for water-based drilling fluid and a preparation method thereof.

The plugging type fluid loss reducer obtained by the method of the invention has excellent performance in reducing drilling fluid fluid loss, the reduction rate is as high as 80%, forms a dense and tough mud cake, and the high-temperature softening and deformation characteristics of the asphalt can timely seal formation cracks and fissures. In addition, the appropriate product formula can be selected according to the characteristics of the application formation and the temperature of the well section. It is flexible to use, and the production process is simple, the conditions are mild, the production efficiency is high, the cost is low, no waste gas and dust are generated, and there is little physical injury to the operators.

Therefore, according to the first aspect of the present invention, there is provided a method for preparing a plugging type fluid loss reducer for water-based drilling fluid, which comprises the following steps:

(1) According to the weight ratio, weigh the following components: 40-90 parts of asphalt, 2-10 parts of surface modifier, and 0-58 parts of release agent;

(2) Spray a surface modifier on the above-mentioned asphalt components during the churning process;

(3) Grinding the material obtained in step (2), preferably in a blower mill, and the mesh size of the obtained sample is 80-200 mesh;

(4) After crushing and discharging, let it enter the dry blender, preferably through a pump, and add the above-mentioned release agent, start the dry blender for dry blending, preferably dry blending for 20min-2 hours, preferably 30min-1 hour, and then discharge to obtain plugging fluid loss reducer, which is optionally stored in bags.

According to the present invention, the asphalt component is one or more of polymer modified oxidized asphalt (PMA), natural asphalt and oxidized asphalt;

The surface modifier may be a mixture of cationic surfactant and water-soluble silicone oil (OSO-W). The function of the cationic surfactant is to make the asphalt component a hydrophilic material. The cationic surfactant is a quaternary ammonium salt cationic surfactant, preferably cetyltrimethylammonium chloride (CTAC), cetyltrimethylammonium bromide (CTAB) or any ratio thereof mixture. The function of water-soluble silicone oil (OSO-W) is to stabilize the water dispersibility of asphalt components and accelerate their immersion time. The water-soluble silicone oil is the water-soluble silicone oil OSO-w produced by Beijing Umitech Nano Material Co., Ltd.

According to the present invention, the weight ratio of the cationic surfactant to the water-soluble silicone oil OSO-w is: 1-5:1-10, preferably 1-3:1-7, more preferably 1-2:1-5.

In this paper, the term "separator" is also called barrier agent, which refers to the solid powder component with auxiliary fluid loss control agent, including cellulose grafted starch (EPPS), polyacrylonitrile ammonium salt (NH ₄ PAN ), Poly(acrylonitrile-acrylamide) ammonium salt (double polyammonium salt) (HMP-21), lignite resin (SPNH), sulfonated lignite (SMC), sulfonated phenolic resin (SMP) or a mixture formed in any proportion. The lignite resin is preferably a sulfonated lignite resin. Any one of these or any mixture of two or more may be used. The dosage of the release agent is preferably 2-58 parts, more preferably 5-50 parts, still more preferably 10-40 parts.

According to a preferred embodiment of the present invention, as the release agent, cellulose-modified starch, lignite resin, poly(acrylonitrile-acrylamide) ammonium salt are used.

According to a preferred embodiment of the present invention, the components and their weight ratios are: 40-80 parts of polymer modified oxidized asphalt, 4-10 parts of surface modifier, 0-40 parts of cellulose-modified starch, 0-40 parts of double polyacrylonitrile ammonium salt, 0-40 parts of sulfonated lignite resin, and the total amount of cellulose modified starch, double polyacrylonitrile ammonium salt and sulfonated lignite resin is 2-58 parts.

According to the second aspect of the present invention, there is provided a plugging type fluid loss reducer for water-based drilling fluid prepared according to the above method, which is characterized in that the following components are weighed according to the weight ratio: 40-90 parts of asphalt, 2-10 parts of surface modifier, 0-58 parts of release agent.

The asphalt component is one or more of polymer modified oxidized asphalt (PMA), natural asphalt and oxidized asphalt.

The surface modifier is a mixture of cationic surfactant and water-soluble silicone oil (OSO-W). The cationic surfactant is a quaternary ammonium salt cationic surfactant, preferably cetyltrimethylammonium chloride (CTAC), cetyltrimethylammonium bromide (CTAB) or any ratio thereof mixture. The water-soluble silicone oil can be the water-soluble silicone oil OSO-w produced by Beijing Umitech Nano Material Co., Ltd. The weight ratio of the cationic surfactant to the water-soluble silicone oil OSO-w is: 1-5:1-10, preferably 1-3:1-7, more preferably 1-2:1-5.

The release agent or blocking agent includes cellulose grafted starch (EPPS), polyacrylonitrile ammonium salt (NH ₄ PAN ), poly(acrylonitrile-acrylamide) ammonium salt (double polyammonium salt) (HMP-21), Lignite resin (SPNH), sulfonated lignite resin (SMC), sulfonated phenolic resin (SMP) or a mixture formed in any proportion. The lignite resin is preferably a sulfonated lignite resin.

According to the invention, preference is given to using cellulose-modified starches, lignite resins or poly(acrylonitrile-acrylamide) ammonium salts as release agents. Further preferably, each component and its weight ratio are: 40-80 parts of polymer-modified oxidized asphalt, 4-10 parts of surface modifier, 0-40 parts of cellulose-modified starch, bispolyacrylonitrile ammonium salt 0-40 parts, 0-40 parts of sulfonated lignite resin, and 2-58 parts of the total amount of cellulose modified starch, double polyacrylonitrile ammonium salt and sulfonated lignite resin.

According to the present invention, the water dispersion stability and adhesion resistance of asphalt materials in water-based drilling fluid can be improved through surface modification and addition of solid powdery release agent. In addition, by selecting different components of the isolation agent and their combinations, plugging fluid loss reducers with different high-temperature resistance properties and applicable formations can be prepared.

According to one embodiment of the present invention, it is preferable to use cellulose grafted starch (EPPS) and/or polyacrylonitrile ammonium salt (NH ₄ PAN ) as the spacer, and the final plugging fluid loss control agent can resist 120°C High temperature, and suitable for shallow formations;

According to another embodiment of the present invention, it is preferable to use poly(acrylonitrile-acrylamide) ammonium salt (bispolyammonium salt) (HMP-21) and/or sodium carboxymethylcellulose (CMC) as a release agent, and the final product The obtained plugging fluid loss reducer can resist high temperature of 150°C, and is suitable for medium and deep formations;

According to another embodiment of the present invention, lignite resin (SPNH), sulfonated lignite (SMC) and/or sulfonated phenolic resin (SMP) are preferably used as the release agent, and the final plugging fluid loss control agent can resist High temperature of 170 ℃, and suitable for deep formations. The most suitable plugging fluid loss control agent can be selected from the above exemplary products according to actual needs.

The plugging fluid loss reducer for water-based drilling fluid of the present invention fully utilizes the characteristics of high-temperature softening and deformation of asphalt materials, and can form a layer of dense and tough mud cake, reducing the penetration of drilling fluid fluid into the formation. And cracks, can be filled and solidified in time, so as to stabilize the well wall, achieve the effect of sealing and preventing collapse, and will not shrink the wellhead and cause problems such as pipe sticking.

In addition, the plugging fluid loss reducer for water-based drilling fluid of the present invention has a fluid loss reduction rate as high as 80% or more, high temperature resistance up to 120-170°C, wide application range, good water dispersion stability, and can pass through the surface Modification and addition of solid powdery release agent can obtain the most suitable products with different high temperature resistance and applicable formations and can be selected according to actual needs.

Detailed ways

The content of the present invention is further explained or illustrated by the following examples. However, the provided examples should not be construed as limiting the protection scope of the present invention.

performance evaluation

1. Sample appearance evaluation:

The samples were visually inspected at room temperature.

2. Fineness evaluation:

Weigh 50.00g of the sample (accurate to 0.01g), put it into a 30-mesh standard sieve, and shake the standard sieve quickly until the sample no longer leaks. Weigh the sieve residue, and calculate the fineness according to formula (1).

$\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span>$

In the formula:

S——fineness, %;

m ₁ ——mass of sieve residue, g;

m——weigh the mass of the sample, g.

3. Evaluation of water dispersion speed:

Use a 100mL graduated cylinder to measure 100mL of distilled water, weigh 1.0g of sample and quickly pour it into the graduated cylinder (the sample should not occupy the wall of the graduated cylinder), start timing at the same time, and observe the time it takes for the sample to be completely immersed in distilled water.

4. Viscosity performance evaluation:

Take 400mL base slurry, slowly add 20.0g sample while stirring, stir at high speed for 20min, maintain at room temperature for 24h under airtight conditions, stir at high speed for 5min, measure the viscosity of the sample solution on a six-speed rotational viscometer according to the provisions of GB/T16783.1-2006 Viscosity of φ600, φ300, φ200, φ100, φ6, φ3, and calculate apparent viscosity (AV), plastic viscosity (PV) and dynamic shear force (YP).

AV=R ₆₀₀ /2

PV=R ₆₀₀ -R ₃₀₀

YP=(2R ₃₀₀ －R ₆₀₀ )×0.511

In the formula: AV﹣apparent viscosity, mPa s;

PV﹣plastic viscosity, mPa s;

YP - dynamic shear force, Pa.

5. Performance evaluation of filtration loss reduction:

Preparation of drilling fluid base slurry: Take 1000ml of tap water, slowly add 50g of sodium soil for drilling fluid test under stirring, stir at high speed for 60min, stop twice during the stirring process to scrape off the clay adhered to the container wall, Then the base slurry was cured for 24 hours at room temperature under airtight conditions. Base slurry performance requirements: API fluid loss is 25ml±5mL, HTHP (120°C) fluid loss is 110ml±10ml. If the performance of the base slurry does not meet the requirements, the amount of sodium soil can be adjusted in proportion.

(2) Measurement of API fluid loss: Take 400mL base slurry, slowly add 20.00g sample while stirring, stir at high speed for 20min, maintain at room temperature for 24h under airtight conditions, measure API fluid loss after stirring at high speed for 5min.

(3) Determination of HTHP120°C filtration loss: Take 400mL base slurry, slowly add 20.0g sample while stirring, stir at high speed for 20min, maintain at room temperature for 24h, and measure HTHP (120°C, 3.5MPa) filtration loss after stirring at high speed for 5min quantity.

(4) Determination of HTHP120°C filtration loss after high-temperature hot rolling: take 400mL of base slurry, slowly add 20.00g of sample while stirring, stir at high speed for 20min, put it into a roller furnace at a specific temperature and roll it at a constant temperature for 16h, take it out and cool After reaching room temperature, stir at high speed for 5 minutes and measure the fluid loss of HTHP (120°C, 3.5MPa).

Example 1

(1) Weigh 200kg polymer modified oxidized asphalt (PMA) and put it on the ground for manual breaking;

(2) Spray 9kg of polyol lipid nonionic surfactant Span80 and 9kg of polyol lipid nonionic surfactant Tween80 during the stirring process for preliminary surface modification;

(3) Transfer the material in step (2) to a blast mill for crushing;

(4) The discharged material enters the dry blender through a pump, and 80kg of cellulose-modified starch is added into the dry blender, and dry blended for 30 minutes, and the discharged material is bagged to obtain a sample, which is designated as NFL-120.

According to the above sample performance evaluation method, the sample of Example 1 is evaluated, and the results are shown in 1.

Table 1 Example 1NFL-120 quality inspection results

Example 2

(1) Weigh 200kg of polymer-modified oxidized asphalt and place it on the ground to break it up manually;

(2) Spray 6kg of industrial-grade liquid CTAB and 12kg of water-soluble silicone oil OSO-w during the stirring process for preliminary surface modification;

(3) Transfer the material in step (2) to a blast mill for crushing;

(4) The discharge material enters the dry blender through the pump, and 100kg of poly(acrylonitrile-acrylamide) ammonium salt (double polyammonium salt) (HMP-21) is added to the dry blender, and it is dry mixed for 30 minutes. bag, get the sample, and record it as NFL-150.

According to the above-mentioned product performance evaluation method, the sample of Example 2 is evaluated, and the results are shown in Table 2.

Table 2 Example 2NFL-150 quality inspection results

Example 3

(1) Weigh 200kg of polymer-modified oxidized asphalt and place it on the ground to break it up manually;

(2) Spray 6kg of industrial-grade liquid CTAB and 12kg of water-soluble silicone oil OSO-w during the stirring process for preliminary surface modification;

(3) Transfer the material in step (2) to a blast mill for crushing;

(4) The discharged material enters the dry blender through a pump, and 45kg of lignite resin is added into the dry blender, dry blended for 30 minutes, and the discharged material is bagged to obtain a sample, which is designated as NFL-170.

According to the above sample performance evaluation method, the sample of Example 3 was evaluated, and the results are shown in Table 3.

Table 3 Example 3NFL-170 quality inspection results

The present invention has been described in detail based on the above-mentioned embodiments. It should be noted that the above embodiments are only for illustrating the present invention. Without departing from the spirit and essence of the present invention, those skilled in the art can design various alternatives and improvements of the present invention, all of which should be understood as falling within the protection scope of the present invention.

Claims (13)

1. A preparation method of a plugging type filtrate reducer for water-based drilling fluid comprises the following steps:

(1) weighing the following components in parts by weight: 40-90 parts of asphalt, 2-10 parts of surface modifier and 2-58 parts of separant;

(2) spraying a surface modifier on the asphalt component in the stirring process;

(3) crushing the material obtained in the step (2), wherein the mesh number of the crushed sample is 80-200 meshes;

(4) after crushing and discharging, feeding the mixture into a dry mixer, adding the separant in the ratio, starting the dry mixer for dry mixing for 20min-2 h, discharging to obtain the plugging type filtrate reducer, and optionally bagging for storage;

wherein,

the asphalt component is one or more of polymer modified oxidized asphalt, natural asphalt and oxidized asphalt;

the surface modifier is a mixture of a cationic surfactant and water-soluble silicone oil (OSO-w);

the cationic surfactant is quaternary ammonium salt cationic surfactant;

the water-soluble silicone oil is water-soluble silicone oil (OSO-w) produced by Beijing Youmettner nano material company Limited;

the weight ratio of the cationic surfactant to the water-soluble silicone oil OSO-w is as follows: 1-5: 1 to 10.

2. The production method according to claim 1,

in the step (1), 6-50 parts by weight of a release agent is added;

the crushing method in the step (3) is carried out in a blast pulverizer;

in the step (4), the mixture enters a dry mixing machine through a pump and is mixed for 30min to 1 hour;

the cationic surfactant is Cetyl Trimethyl Ammonium Chloride (CTAC), Cetyl Trimethyl Ammonium Bromide (CTAB) or a mixture formed by any proportion of the Cetyl Trimethyl Ammonium Chloride (CTAC) and the Cetyl Trimethyl Ammonium Bromide (CTAB);

the weight ratio of the cationic surfactant to the water-soluble silicone oil OSO-w is as follows: 1-3: 1 to 7.

3. The production method according to claim 2,

in the step (1), 10-40 parts of a release agent by weight;

the weight ratio of the cationic surfactant to the water-soluble silicone oil OSO-w is as follows: 1-2: 1 to 5.

4. The production method according to claim 1,

the separant is cellulose grafted starch or polyacrylonitrile ammonium salt (NH)₄PAN), poly (acrylonitrile-acrylamide) ammonium salt, lignite resin (SPNH), sulfonated lignite (SMC), sulfonated phenolic resin (SMP) or a mixture thereof in any proportion,

the lignite resin is sulfonated lignite resin.

5. The production method according to claim 1,

the separant is cellulose modified starch, lignite resin or poly (acrylonitrile-acrylamide) ammonium salt.

6. The production method according to claim 1,

the components and the weight ratio thereof are as follows: 40-80 parts of polymer modified oxidized asphalt, 4-10 parts of surface modifier, 0-40 parts of cellulose modified starch, 0-40 parts of ammonium salt of bi-poly acrylonitrile, 0-40 parts of sulfonated lignite resin, and 2-58 parts of the total amount of the cellulose modified starch, the ammonium salt of bi-poly acrylonitrile and the sulfonated lignite resin.

7. The plugging type fluid loss agent prepared by the method according to claim 1 is characterized by comprising the following components in parts by weight: 40-90 parts of asphalt, 2-10 parts of surface modifier and 2-58 parts of separant.

8. Plugging fluid loss additive according to claim 7,

the fluid loss agent comprises the following components in parts by weight: 40-90 parts of asphalt, 2-10 parts of surface modifier and 6-50 parts of separant.

9. Plugging fluid loss additive according to claim 8,

the fluid loss agent comprises the following components in parts by weight: 40-90 parts of asphalt, 2-10 parts of surface modifier and 10-40 parts of separant.

10. Plugging fluid loss additive according to claim 7,

the release agent comprises cellulose grafted starch and/or polyacrylonitrile ammonium salt (NH)₄PAN)。

11. Plugging fluid loss additive according to claim 7,

the release agent comprises a poly (acrylonitrile-acrylamide) ammonium salt and/or sodium carboxymethylcellulose (CMC).

12. Plugging fluid loss additive according to claim 7,

the release agent comprises lignite resin (SPNH), sulfonated lignite (SMC) and/or sulfonated phenolic resin (SMP).

13. Use of a blocked fluid loss additive made according to the process of any one of claims 1 to 6 or a blocked fluid loss additive according to any one of claims 7 to 12 for water-based drilling fluids.